1. Field of the Invention
The present invention relates to a method for adapting steering a motor vehicle.
2. Description of Related Art
With a conventional steering system, steerable wheels are steered by a driver via an actuation unit, more preferably through twisting a steering wheel. The rotating of the steering wheel causes a displacement of a rack which in turn pivots the wheels. In power steerings the steering movement of the driver is supported through an additional electric motor. Here, the steering support is generally performed through characteristic-controlled or regulated systems where the steering support is applied as a function of the vehicle speed.
In addition, steering systems are known where no mechanical connection exists between the steerable wheels and the steering wheel (steer by wire). Here, the wheels are pivoted as a function of the rotational speed of the steering wheel with the help of appropriate motors. A substantial problem of these systems consists in that the driver does not receive any perceptible feedback from the wheels any longer.
In addition to influencing the steering behaviour as a function of the speed systems are also known which enable active return of the steered wheels or compensate for side wind. So-called pull/drift compensation methods are also known.
Compensation of drive influences due to the geometry on the steering moment (torque steer) because of uneven-length drive shafts which are described via a fixed correlation between drive moment and steering moment and which go beyond global pull/drift compensation, is absent.
Compensation of drive influences due to the geometry on the steering moment (torque steer) because of the moment distribution of all-wheel systems which are described via a fixed correlation between the distribution of the drive moment to the front wheels and steering moment and which go beyond global pull/drift compensation is likewise absent.
Neither are systems known where compensation of drive influences on the steering moment (torque steer) due to a different distribution of the drive moment to the front wheels, conditional upon different friction values on said front wheels takes place which are described via a fixed correlation between the distribution of the drive moment to the front wheels and steering moment and which go beyond global pull/drift compensation.
Compensation of drive influences on the steering moment (torque steer) due to different distribution of the brake moment on the front wheels conditional on different friction values on said front wheels which are described via a fixed correlation between the distribution of the brake moment to the front wheels and steering moment and which go beyond a global pull/drift compensation is not known either.
Since pull/drift compensation acts permanently and rather globally and unspecifically said pull/drift compensation generally distorts the feedback on the driving state since it also acts when the abovementioned drive influences are absent and it is no longer required.
In principle no systems are known where the steering characteristics are regulated as a function of the condition of the road, the friction value distribution between the wheels (μ-split), the dynamic driving state of the vehicle, more preferably the non-stationary state, the behaviour of the vehicle driver and the route profile.